The proposed project seeks to prevent two common, persistent, and disabling mental health problems of children: 1) acting-out, aggressive behavior disorders; and, 2) withdrawn, overly inhibited behavior disorders. It also seeks to prevent the academic failure that is often associated with behavior disorders in children. The strategy of the proposed intervention is to promote competencies largely incompatible with the respective problem patterns mentioned above: competencies in 1) cooperation, compliance, and kindness; 2) active, interested social interaction; and, 3) proficient use of language. Subjects are socioeconomically disadvantaged children three to five years old, in inner-city day care centers. The proposed intervention entails one-to-one contact, four to five times weeklyfor one year, between the experimental subjects and the "preceptors," who are lay persons trained to promote the competencies. The method involves two activities developmentally appropriate for these preschool children: symbolic play, and the reading and telling of stories. By these activites, the preceptor employs symbolic modeling of the above-mentioned skills. The preceptor uses attention and approval as contingent reinforcement to encourage the child to enact fantasy rehearsals of the positive patterns in the child's storytelling and symbolic play, as well as in the child's real-life interactions. Standard written and videotaped training materials for preceptors will be refined, so that the intervention technique can be enacted independent of any particular individual, and so that the independent variable can be highly specified. The proposed research is a test of the efficacy of this method. The proposed study involves three cohorts comprising 60 preschool children in each cohort for each of three years. Thirty of each cohort will be randomly assigned to the experimental intervention; the other thirty to a minimal contact control group. Measures of psychological/behavioral functioning and language ability will be employed at pretest, posttest, and at follow-up six to nine months after the intervention ends. All raters and testers will be blind to the program-versus-control status of the children.